Carburetor



Nov. 16, 1937. E G. ATKINS 2,099,553

CARBURETOR Filed oct, 9, 1933 2 shew-sheet 1 Nov. 16, 1937. l EJG, ATKINS I 2,099,553

CARBURETOR Filed Oct. 9, 1955 2 Sheets-Sheet 2 ll Ewa@ G. mmm,

llllllrl/lll/ Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE CARBURETOR Edward` G. Atkins, Jackson, Mich., assignerv to E G A Carburetor Co., Jackson, Mich., a corporation of Michigan Application October 9,

12V Claims.

This invention relates to carburetors and it is more particularly adaptable to carburetors for interna-l `combustion engines usedA in automobiles andl is of the same general type asthat disclosed 5 in myfPatent No. 1,787,230 issued December 30th,

An object of the invention is to provide a carburetor which will obtain its supply of fuel, which is usually gasoline, from a tank located l either above or below the level of the carburetor and will maintain a substantially uniform level of gasoline in the carburetor irrespective of the Arelative level of the gasoline in the supplyv tank.

A further object of the invention is to provide 15 a carburetor which will supply a proper mixture of fuel and air under the full range of running conditions to'which it is subjected. Another objectl ofthe invention is to provide a carburetor which utilizes the gas evaporated from the gaso- 20 line in the iioat chamber of the carburetor and provides a constant suction within the float Achamber which will prevent air locks in the gasoline supply pipe.

The invention provides various new and useful features of construction and arrangement as hereinafter more fully described and particularly pointed out in the claims, referencefbeing had to the accompanying drawings, in which,

Fig. l is a vertical sectional elevation of the :i0 carburetor embodying this invention, taken on the line I-I of Fig. 4.

Fig. 2 is a fragmentary section of the same taken on the line 2--2 of Fig. 4.

Fig. 3 is a fragmentary cross section of the :l ejecting nozzle ta-ken on the line 33 of Fig. 1.

Fig. 4 is a plan-view, with the cover removed, of the carburetor with the throttle neck and suction chamber removed.

Fig. 5 is a verticalv sectionrthrough the float 40 portion of the carburetor taken on the line 5-5 of Fig. 4.

Fig. 6 is a transverse vertical section on the line 6-8 ofV Fig. 4.

Fig. '7 is a vertical section of the dash pot on 45 Vthe line '1 -1 of Fig. 4, and

Fig. 8 is a fragmentary vertical section of the air inlet valve on the line 8--8 of Fig. 4.

Like numbers refer to like parts in allv of the figures.

I represents the throttle neck which is attached to and communicates with the intake manifold of an internal combustion engine and is provided with the conventional throttle valve 2. The suction andV mixing chamber `3 is attached to and '55 communicates with the throttle neel; I and has 1933, Serial No. 692,774

one side of the mixing chamber 3'; the bodies of the two chambers being preferably formed separately and joined by` screws 'I by means of whichY their relative axes may bealtered to accommodate different conditions of installation. In other words, it is necessary to. have the axis of the float chamber substantiallyvertical while the carburetor neck may be attached'` to the manifold of the engine at different angles. depending upon the construction of the engine, and the screw connection. Iv willpermit the 'float chamber to be mounted with. its axis vertical regardless of the position of the throttle neck and mixing chamber.

The suction valve 5 hasa stem 8A which is slidably mounted in a guide 9 and is provided with an extension in the nature ofa push rod I0 mounted-in a guide I I. This division of the valve stem 8 and push rod I0 is for convenience of construction and assemblyand Vthe two members .can be integral if preferred.

Fuel ejecting passages I2 are located'atfoppositesides ofthe valve stems, extending through the same element 9 in which the valve stem guide is located and these passages communicate outwardly with thel mixing chamber 3 and inwardly with a chamber I3' surrounding the push rod I 0. A U-shaped passage I4communicates with the float chamber above the gasoline level and also-with the chamber I3' and the gasoline control valve I5admits gasoline from the float chamber to the passage I4 as hereafter described. Y It will be understood that suctionk produced by the engine will open the suction valve. 5 to admit air through the passage 4 and this move'- ment actuatesthe valve stem 8' and the pushr rod I5 to move thebell crank lever having anA arm I6 and pivoted within the float chamberat I1.. The bell crank lever has a transverse body portion I8 from which a short arm I9 extends and also has an arm 25 upon the swinging end of which the contact rollers 2| are mounted.

The bell crank lever operates, to openV and close the gasoline control valve l5 in synchronism with movement of the Ysuction valve 5 and the gasoline control valve I5 is provided with a spring 22. acting to close it and also, through connections hereafter described, to close the suction valve 5 and; a spring 2.",` in a dash-pot 24,. acting against the rollers, 2| on the arm 2D of the bell crank,

alsctemis to close the suctiony valve 5v and open.-

ing movement of the suction valve acts against the tension of both of the springs 22 and 23.

A rocking lever 25, supported on an adjustable fulcruln 26, has one end pivotally connected at 21 to the gasoline control valve I5 and its opposite end is connected by a link 23 to the short arm I9 of the bell crank lever. By this connection opening movement of the suction Valve 5 produces opening movement of the gasoline valve I5.

It is desired to dampen or prevent too rapid opening movement of the suction valve 5, this being accomplished by the piston 29 operating in the dash pot 24 against tension of the spring 23. The dash pot 24 has a vent passage 39 communicating with its upper end and extending downward into the float chamber below the gasoline lever which constitutes a restricted outlet and permits a relatively slow upward movement of the piston 29 in the dash pot. This vent passage, having its outlet below the gasoline level, insures that the dash pot is cleared of air and is full of gasoline to avoid the compressibility of air interfering with the operation of the dash pot. A valve 3| at the lower end of the piston 29 closes on upward movement of the piston and opens upon downward movement thereof which permits a free downward movement of the piston.

It is realized that the tension of the spring 23 Vwill be increased to some extent as it is compressed and the arc of travel of the arm 29 of the bell crank is arranged to increase its power in its action against the piston 29 as the spring 23 is compressed thus maintaining a substantially constant effort against opening of the suction valve 5 throughout its range of travel.

The fulcrum 26, which supports the rocking lever 25, is mounted for adjustment longitudinally of the lever 25, being formed on a slide 32 which is seated on a saddle 33. The slide 32 has slots 34 through which the Valve I5 and a pin 35 extend to guide the slide in its longitudinal movement. An adjusting screw 36 projects through the wall of the float chamber, has its inner end connected to the slide 32, and serves as a means for moving the slide longitudinally on the saddle 33 and retaining it in its adjusted position. The connection between the screw 36 and the slide 32 permits relative vertical movement.

The saddle 33 is attached to the upper end of a rod 31 which extends downwardly through the body of the structure and has its lower end exposed outside of the carburetor. An adjusting lever 38 is pivoted at one end in a short bracket 39 and has its opposite end supported by an adjusting screw 4U, the rod 31 engaging the lever 38 between its ends and being adjustably supported thereby. Movement of the adjusting screw 49 raises or lowers the saddle 33 with the parts supported thereon and the lever 38 may be abnormally raised by suitable connections (not shown) to serve as a primer, which raising movement lifts the valve I5 from its seat to permit an abnormal passage of gasoline for the purpose of starting the engine.

Gasoline is admitted to the float chamber 5 through a float valve 4I of suitable conventional form, the valve being in communication with the source of gasoline supply by the pipe 42. A float 43 is located within the float chamber and is provided with a lever 44 which is pivoted at 45 and has its moving end connected with the oat valve 4I. This valve and its controlling float operate in the usual manner to close the valve when the liquid in the float chamber has raised to a predetermined level and to open the valve when the liquid falls belo-W that level.

Air is admitted to the float chamber above the liquid level through a port 46 extending through the wall of the float chamber and com.- municating with a weighted air valve 41. The air valve 41 is normally held against its seat to close the air intake passage by a weight 48 but will raise to open the air passage upon attainment of a sufficient degree of vacuum within the float chamber to lift the Weight, such vacuum being attained by suction from the engine transferred through the passages I2, the chamber I3, the U-shaped passagel4 and the gasoline valve I5 which communicate with the float chamber E.

The capacity of the valve 41 is as great or greater than the combined capacity of the passage I4 and valve I5 whereby a greater degree of Vacuum will be maintained in the mixing chamber 3 than in the float chamber 6.

Operation Assuming that the carburetor is properly attached to the manifold of an internal combustion engine and that the supply pipe 42 is in communication with a gasoline tank which, for example, is below the level of the carburetor, and that the throttle 2 is properly connected to be manually operated, the engine is started and the suction therefrom acts upon the suction valve 5 to open it to permit air to pass through the air passage 4. The Vacuum valve 5 opens more or less depending upon the opening of the throttle valve 2 but at all times it sufficiently closes the passage 4 to restrict the passage and set up a vacuous condition in the chamber 3.

The vacuum in the chamber 3 is transferred through the passages I2, the chamber I3 and the U-shaped passage I4 and draws gas from the oat chamber above the gasoline level and also gasoline through the control valve I5, the gas and gasoline mixing together in the chamber I3 and the passages and is emitted from the passages I2 into the chamber 3 where it mixes with the incoming air and enters the engine as a combustible gas. A

The amount of gasoline entering the engine is governed by the control valve I5 and is in substantially direct ratio to the amount of air drawn in through the passage 4. The suction valve 5 opens to a greater or less degree depending upon the Volume of air passing through the passage 4 and this movement of the suction valve 5 is transmitted to the gasoline control valve E5 in substantially uniform ratio. When the suction valve 5 is closed, as when the engine is not operating, the control valve I5 is in its nearest closed position. This position may be entirely closed or partially open according to the conditions for which the carbureter is adjusted. Opening movement of the suction valve 5 correspondingly opens the gasoline control valve I5 and when the throttle valve 2 is opened to admit a greater amount of gas the suction valve 5 likewise opens to permit the inlet of a greater amount of air and the gasoline control valve I5 opens in a like degree to admit the passage of a greater amount of gasoline.

The device may be adjusted as to the amount of opening of the valve I5 and also as to the rate f of opening relative to movement of the suction valve 5. The amount of opening of the valve l5 is regulated by the adjusting screw 43 which, through the supporting lever 38, moves the rod 31 and the saddle 33 at its upper end upon which the slide 32, having`y the fulcrim 26; issupported; This adjustment ofthe screw 410-, therefore,.moves the valve I5'. upward or downward and may be termedV the idling adjustment. The rate of opening of the valve t5 is. adjusted by means of the' screw 36' which moves'` thel slide 3.2 carrying the fulcrum- 261l lengthwise uponthe saddle 33; Movement of this-slide changes the location of the fulcrum 26? relative to-theleverY 251Which results in a greater or less movement' of-the valve I5 relative to movement of the suction valve 5.

Whilethe engine is in operationl there is always alvacuouscondition existing in the float chamber Si because the Vacuum: valve 5 aotuates to resist entrance of' air intov the chamber 3 and causing a vacuous condition in 'this' chamber whichr is transferred through the passages I2, the chamber I3 and the U-shaped passage I4 to the iioat chamber. 'I'he weighted air' valve 41 resists entrance of air from the exterior of the carburetor into the float chamber sufficiently tok cause vacuum to exist in the floaty cham-ber and this valve is sufficiently weighted so that the degree of vacuum attained in the float chamber is sufficient to cause gasoline to flow through the-float valve 4 I. andthe supply pipe 4-2 to the desired height.

In other words, the airv valve 41 and itsweight will prevent entrance of air to the float chamber through the passage 46 until sufficient vacuum isattained within the float chamber to raise gasoline from the lowest level desired under operating conditions. Upon attaining th'e'predetermined degree of vacuum inthe float chamber the air valve 41 will openl to vpermit air to enter the float chamber.y and this passage of Yair into and through the. fioatchamber and out-through the U-shaped passage I4 has. the result of removing gas accumulated in the floatr chamber by evaporation to be mixed with the gasoline for combustion and also preventsl air locks occurring in any part of the system. f

The level ofthe gasoline in the float Achamber is controlled by the float 43 and'v float valve 4I in thek usual way. The float will cause the noa-t valve tov close when the predetermined level of fluid has been attained and this action will occur` Whether the level of the fluid supply is above or below the level of fluid inthe oat chamber so that a constant level of gasoline is maintained in the oat chamber under all operating conditionswhere the fuel supply levelv may change such as when the level of the vehicle is changed in going, up and down hill, etc. A. quick opening action or: fluttering of the suction valve 5 and its connected parts is preventedv by the piston` 23 operating in the dash pot 24. This piston can have; only al relatively slow upward movement because of the restricted passage of liquid out of the dash pot. Return or closing movement of the suction valve 5 and also the gasoline control valve I5 is unimpeded by action of the dash pot because the valve 3| will open upon downward movement of the piston 29 permitting free ingress of gasoline into the dash pot.

Although this specification sets forth the structure as creating and maintaining a constant Vacuum in the mixing chamber and the float chamber it is realized that the degree of vacuum probably varies. The ystructure acts in a manner which tends to create and maintain a constant vacuum and if the degree of vacuum fluctuates the device acts rapidly to return it to balance or predetermined degree. Therefore the definition of the term constant vacuum is to be interpreted as meaning a practical or substantially constant y 1. In a carburetor; the combination of' a fuel reservoir, a connection leading from said reservoir ton a source of liquid fuel supply, means for maintaining a constant liquid fuel' level, less than full, in said reservoir; a main air passage leading to theintake of an internal combustion engine', spring valveI means, leading' from atmospheric pressure to the main air passage, said mainair passage having a cross sectional area 'capable of deliveringthe maximum requirements of the engine; a fuel conduit to the main air passageI communicating with the fuel reservoir below the liquid level therein through a port, said port supplying the major portion of the fuel,

f abranch passageof` restricted cross sectional area leading from said fuel conduit tothe fuel reservoirabovefthe-liquid level therein, said fuel conduit and branch passage being so dimensioned and positioned relative-to each other andu to themain air passage as to cause .the pressure reduction withinthe main air passage to be directed more tc said port than to the space above the' liquid level for the purpose described.

2. A carburetor as set forth in claim 1' but also having'means actuated by the inward movement of said spring, valve-r4 means for increasing the effective area ofvk said port in a predetermined varying ratio.

3. A carburetor as set' forth in claim 1 but also having means for diminishing the normal increased pressureexerted by compression of the spring on the opening movement of the spring valve means including` a lever arm cooperatively associated with the spring of the spring valve means to vary the leverage therebetween.

4'. A carburetor as sety forth in claim lr and also having means, actuated by theinward movement of' said, spring valve means for .increasingV the effective areaof said port in a predetermined varying ratio and means for diminishing the1nor'- mal increased pressure exerted byA compression Vof .the spring on the opening. movement of' the lsprlng valve means including a leverl arm co;-

operatively associated Awith the. spring of the spring valve means to vary the leverage' therebetween.

5. In a carburetor', the combination of a fuel reservoir, a connection leading from saidL reservoir to a source of liquid fuel supply; means for maintaining a constant liquid' fuel' level, less than full, in said reservoir; a main air passage leading to the intake of an internal combustion engine, spring valve means, leading from atmospheric pressure to the main air passage, said main air passing having a cross sectional area capable of delivering the maximum requirements of the engine; a continuous passage of restricted cross sectional area from the upper part of the fuel reservoir above the liquid level therein, to said to Ithe others being predetermined by the location of the arcs of travel for the purpose described.

'7. A carburetor comprising, a closed liquid chamber having two compartments therein, one compartment having a valved fuel inlet communicating with a liquid fuel supply, means actuated 'by the level of liquid in the compartment to actuate said valve to maintain a level of liquid in the chamber less than full, the other compartment having a dashpot mechanism located therein, a yieldingly closed air inlet leading into the first mentioned compartment above the uppermost plane to which the liquid therein rises, a `valved outlet leading from the said liquid compartment below the liquid level, said valved outlet communicating with the intake passage of an internal combustion engine, a second Outlet leading from Ithe said liquid compartment above the liquid level likewise communicating with said intake passage of the internal combustion engine, means for increasing thesize of the valved outlet from the said liquid compartment in proportion to the vacuum induced within the intake passage of said internal combustion engine and means cooperatively associated with the said valved outlet and the dashpot to dampen its movement.

8. A carburetor comprising, a mixing chamber adapted to be connected with the intake passage of an internal combustion engine and having an air inlet, yieldable means opened by suction from the engine and closing said air inlet, a closed liquid chamber having a valved inlet communicating with a source of liquid fuel supply, means actuated by the level of the liquid in the chamber to actuate said valve to maintain a level of liquid in the chamber less than full, a passage communicating directly between the liquid chamber above the liquid level and the mixing chamber, an air valve to the liquid chamber above the liquid level, a valved outlet from said liquid chamber having at least a portion thereof below the liquid level, means actuated by movement of said yieldable means leading to the mixing chamber to govern the opening of said valved outlet whereby liquid fuel is permitted to pass through said valved outlet, said inlet air valve providing for a predetermined amount of vacuum above the level of the liquid fuel at all times, said outlet passageway leading from above the liquid, being unrestricted by any valve whereby some vacuum, under operating conditions, is produced whereby the lighter ends of the liquid fuel will be drawn through this passageway and vapor lock prevented. i

9. A carburetor as set forth in claim 8 in which the passage between the liquid chamber above the liquid level and the mixing chamber includes a portion of a U-shape, and in which the valved outlet from the liquid leads into the medial part of said U-shape for the purpose described.

10. In a carburetor, the combination of an air admission valve arranged to actuate a fuel admission valve, a spring for normally holding said air valve to its seat and against which said air valve acts throughout its travel, means constituting a leverage between said air valve and spring through which the action of the latter is transmitted to said air valve, said means being so shaped and located With said air Valve closed that the effective leverage between the valve and spring is increased as the valve opens to compensate for the increase in the resistance in said spring.

l1. In a carburetor, the combination of an air admission valve arranged to actuatea fuel admission valve, a spring for normally holding said valve to its seat and against which said valve acts throughout its travel, means constituting a leverage between said valve and spring through which the action of the latter is transmitted to said valve, said means including two lever arms associated with said spring and valve and pivoted about a Ycommon aXis as a unit, said levers being so disposed with reference to the direction of operation of said valve and spring that the effective leverage between the lever associated with said valve increases upon opening movement of said valve and the eiective leverage between the lever associated with said spring decreases whereby the increasing resistance of the spring upon opening of the valve is compensated.

12. A carburetor, comprising an air admission valve arranged to actuate a fuel admission Valve, a spring continuously urging said air valve toward a closed position and giving increasing resistance upon opening movement of said valve, a lever structure for actuating said fuel valve and for directing the stress of said spring against said air valve, the portion of said lever structure actuating said fuel valve being so shaped and located with said fuel valve in a closed position as to impart a greater degree of travel of said fuel valve during the early range of movement of said air valve than during the latter range of movement of said air valve, the portion of the lever structure operatively connecting said spring and air z valve being so shaped and located as to have an increasing effective leverage favoring said air Valve to compensate for the build-up of said spring during the travel of said air valve from closed to open positions.

EDWARD G. ATKINS.

Cil 

